Method and apparatus for handling image data after unsuccessful transfer to remotely located device

ABSTRACT

A computerized imager is programmed with software that allows properly formatted image frames (objects) to be sent to one or more remotely located devices selected from a list of configured devices. For each job selected for transfer to a remote device, an element is added to a linked list which forms a virtual queue, each element incorporating a respective pointer (i.e., the file name) identifying each stored image to be included in that particular job. Each element identifies the image frames included in the job and the destination remote device for that job. Elements for failed jobs are transferred to a Holding Queue. An interactive display menu enables the operator to easily redirect the failed jobs to a secondary remote device by clicking on the menu.

FIELD OF THE INVENTION

This invention generally relates to imaging systems used in medical diagnostics. In particular, the invention relates to the transfer of digital images from an ultrasound imaging system over a network to remote devices for archiving and/or printing.

BACKGROUND OF THE INVENTION

Conventional ultrasound imagers create two-dimensional images of biological tissue by scanning a focused ultrasound beam in a scan plane and for each transmitted beam, detecting the ultrasound wave energy returned along a respective scan line in the scan plane. A single scan line (or small localized group of scan lines) is acquired by transmitting focused ultrasound energy at a point, and then receiving the reflected energy over time. The focused transmit energy is referred to as a transmit beam. During the time after transmit, one or more receive beamformers coherently sum the energy received by each channel, with dynamically changing phase rotation or delays, to produce peak sensitivity along the desired scan lines at ranges proportional to the elapsed time. The resulting focused sensitivity pattern is referred to as a receive beam. A scan line's resolution is a result of the directivity of the associated transmit and receive beam pair.

A B-mode ultrasound image is composed of multiple image scan lines. The brightness of a pixel on the display screen is based on the intensity of the echo returned from the biological tissue being scanned. The outputs of the receive beamformer channels are coherently summed to form a respective pixel intensity value for each sample volume in the object region or volume of interest. These pixel intensity values are log-compressed, scan-converted and then displayed as a B-mode image of the anatomy being scanned.

If the ultrasound probe is swept over an area of body, a succession of image frames (corresponding to spaced slices intersecting the body being examined) can be displayed on the monitor. In one type of ultrasound imaging system, a long sequence of the most recent images are stored and continuously updated automatically in a cine memory on a first-in, first-out basis. The cine memory is like a circular image buffer that runs in the background, capturing image data that is displayed in real time to the user. The cine memory acts as a buffer for transfer of images to digital archival devices via the host computer. When the user freezes the system (by operation of an appropriate device on an operator interface), the user has the capability to view image data previously captured in cine memory. The image loop stored in cine memory can be reviewed on the display monitor via trackball control incorporated in the operator interface, and a section of the image loop can be selected for hard disk storage.

If the transducer probe was moving during image acquisition, the succession of image frames stored in cine memory form a three-dimensional data volume of image information. This data volume can be used by the system computer to project a three-dimensional view of the area of interest. This projected image can be returned to memory and then displayed on the monitor. Any acquired or projected image can be stored internally on the system hard disk or on a magneto-optical disk (MOD) inserted in a disk drive.

In addition to storing images internally, modern ultrasound imaging systems need to be able to transfer images to various types of remote devices via a communications network. To successfully transfer images, the relevant networking features of the ultrasound imager must be compatible with the networking features of the destination remote device. In particular, the ultrasound imager must place the data to be transferred in a format which can be handled by the destination remote device. An attempt to accomplish the foregoing is the adoption of the DICOM (Digital Imaging and Communications in Medicine) standards, which specify the conformance requirements for the relevant networking features. The DICOM standards are intended for use in communicating medical digital images among printers, workstations, acquisition modules (such as an ultrasound imaging system) and file servers. The acquisition module is programmed to transfer data in a format which complies with the DICOM standards, while the receiving device is programmed to receive data which has been formatted in compliance with those same DICOM standards.

DICOM involves more than digital image transfer. DICOM functionality includes the following Service Classes: archive/transfer images: store (across network); archive/interchange images: media storage; query for information and retrieve images; make image hard copies: print management; patient, study and results management; radiology information system modality: worklist management; and test connectivity: verification. A fundamental concept employed in DICOM is "Services on Objects". One example of an "Object" is an ultrasound image. Two examples of a "Service" are the "Store" and "Query/Retrieve" functions. In DICOM, methods of operating on information objects are referred to as "Service Object Pair Classes" (SOP Classes). Examples of SOP Classes are "Store an ultrasound image", "Print an ultrasound image", "Find which studies there are for a certain patient", "Retrieve all studies of a certain patient" and "Retrieve a worklist". Unique Identifiers (UIDs) are defined for all SOP Classes. UIDs are also given to all studies, series and images. These UIDs are, for instance, used for retrieval. In the DICOM vernacular, a patient has a study which comprises a study component, e.g., examination using a particular modality. Images acquired in sequence in the course of a study on a patient form a series of objects.

The DICOM system is based on the client/server concept. The device which uses a service (on objects) is the client device, while the device which provides the service is the server device. The client device is referred to as a Service Class User (SCU), while the server device is referred to as a Service Class Provider (SCP). The SCU sends a Service Request to the SCP over a local area network (LAN). The SCP sends back a response to the SCU over the same LAN. If the response is affirmative and a communications syntax is agreed upon, an association between the SCU and the SCP is opened and data can be transferred between the two devices. In the DICOM system a device is not limited to one role: it can be both SCU and SCP at different times.

The DICOM system is designed to facilitate the communication of digital images of different types, e.g., X-ray, computerized tomography, magnetic resonance and ultrasound imaging. In an ultrasound imager having conventional DICOM capability, three local real-world activities occur: Image Send, Image Print and Remote Verification. Image Send and Image Print can be done in either automatic or manual mode. Verification of remote DICOM devices configured on the ultrasound imager is performed when the imager is powered up or when requested by the system operator.

All DICOM activities are handled in a queued manner by application software running on a host computer incorporated in the imager. In one type of ultrasound imager, the user can select any image in cine memory to be sent in DICOM format via a LAN to a remote device having DICOM capability. The host computer of the ultrasound imaging system is programmed with DICOM system software which facilitates transmission of image frames from the cine memory to the remote DICOM device via the host computer hard disk and the LAN.

In the conventional ultrasound imager, Image Send can be used in automatic or manual mode, depending on the user configuration. When automatic mode is configured, console keys are used to capture the image and to store it on the hard disk. The request is queued to a DICOM queue manager (preferably implemented in software), which requests an association with the destination remote device. After the association with the remote device has been opened, the queue manager "pushes" the image to the remote device without user intervention. The transfer is done in the background while scanning or other operator activities continue. In manual mode, the captured images are archived on the hard disk or on a MOD during the exam(s). Upon completion of the exam(s) the images are tagged using an archive menu and queued to any of the network devices that have been configured on the imager. The images are sent sequentially in the background while scanning or other operator activities proceed. Image Print works much the same way as Image Send, in both automatic and manual modes, the only difference being that the destination device is a printer.

In order to accomplish image transfer, the ultrasound imaging system must know the configuration of the destination remote device prior to attempting to communicate with that device. The configuration data for the destination remote device is typically inputted to the ultrasound imager during software installation by a field engineer, although the DICOM network can be configured at any time. When the imager receives an instruction to transmit data to a particular remote device from the system operator, the imager software converts the image data to be transferred into the DICOM format required by the destination remote device, based on the configuration data for that device stored in system memory. The imager also sends a request over the network to the destination remote device to open an association, i.e., to connect the imager to the destination remote device.

If the remote device responds in the affirmative, the imager and remote device then agree on which SOP Class is to be used and which device will act as the server and which as the client. The ultrasound imager also selects the appropriate encoding syntax from those accepted by the remote device. Other communication parameters are also negotiated.

After the DICOM communications protocol has been settled, the association is opened and the imager attempts to send the DICOM-formatted image file (object) to the remote device via the network. The transfer is done in the background while scanning or other operator activities continue. If the remote device is a storage device, each image file is transferred singly in response to a Send request inputted by the operator. The conventional imager with DICOM capability will open an association with a storage device in response to each "send to a storage device" instruction. If a transfer is successful, the association for that transfer is immediately closed. If the remote device is a printer configured to print multi-image film, then a number of images are accumulated to make up a multi-image film and an association is opened in response to a Send instruction when a number of images sufficient to fill the multi-image film have been accumulated. After the full film session of images has been transmitted, the association between the imager and printer is closed.

If the destination remote device sends back a message indicating successful receipt of the transmitted data, the DICOM-formatted image file can be deleted from the imager memory. Alternatively, the system operator can instruct the imager to retain the DICOM-formatted image file on the imager hard disk or to store it on a MOD inserted in the imager.

The remote device to which the ultrasound imager sends data can be a printer, a storage device or other device. If the operator interface of the imager has only one configurable Print/Store button, then that button will be configured to initiate data transfer to the destination remote device. The configuration data for the remote device will indicate the type of device to the imager and then the imager will format the data being transferred accordingly. If the operator interface has multiple Print/Store buttons, then each button can be configured to initiate data transfer to a respective remote device. Data transfer to any one of those configured remote devices can then be initiated by pressing the appropriate Print/Store button.

In addition to the digitized image (i.e., pixel data), the DICOM object transferred from the ultrasound imager also includes attribute information. For example, the attribute information may include patient attributes (e.g., patient name and patient identification number), study attributes (e.g., accession number and study date), series attributes (e.g., modality type and series date), and image attributes (e.g., image type and numbers of rows and columns). Each attribute has a name, a value representation and a tag. A tag is a number unique to the attribute. The value representation defines what type of value the attribute can have (e.g., a 64-character string, binary data, etc.).

In accordance with DICOM standards, there are three types of attributes. Type 1 comprises attributes which are mandatory and must always be present with a value; Type 2 comprises attributes which are mandatory but are allowed to be empty; and Type 3 comprises attributes which are optional and are also allowed to be empty. An incompatibility between two devices may arise, for example, if the receiving device requires that a Type 3 attribute be transmitted while the sending device does not include that attribute in its transmission. As a result, even if both devices are configured in accordance with current DICOM standards, the data transfer cannot occur.

Thus, even mutual conformance to DICOM standards does not guarantee that two devices can be compatibly connected to each other.

In accordance with a further aspect of the DICOM system as currently implemented, an ultrasound imaging system can retrieve a worklist from a Radiology Information System (RIS) at a hospital via the LAN. The retrieved worklist may, e.g., comprise all patients to be examined on a particular day using that particular ultrasound imager. The worklist includes the following information for each patient: name, identification number, sex, birth date, accession number, study data, etc. The information retrieval is initiated by the ultrasound imager. In response to this query, the RIS transmits the worklist to the ultrasound imager, which stores it in memory. This worklist is then available for viewing by the sonographer. The patient currently being examined can be selected from the worklist.

In order to protect against image data loss due to a failed attempt to send image data from an imager to a remote device on a network, the user must also store that image data in a local storage device, e.g., the hard disk. These images stored in the hard disk must be manually removed at the end of the day or when the hard disk is full. This procedure has the disadvantages that the wrong images could be accidentally deleted; sorting through the images is difficult and prone to user error, which could result in the wrong images being printed; and more time between patient exams is required in order to perform manual image cleanup. In addition, if the imager's primary storage system or printer has a failure that cannot be corrected immediately and if the imager is implemented in such a way that the image data for the failed data transfer is lost, then the result is that the patient being examined must be rescheduled and re-scanned.

Because the DICOM capability is implemented in software, these features of the ultrasound imaging system can be readily upgraded. One goal of such upgrades is to increase the efficiency of the system operator by making the system simpler to operate, e.g., by requiring fewer manipulations to activate a particular operation. Another goal of system upgrades is to increase the ability of the imager to connect rapidly, efficiently and reliably to remote devices on the network, i.e., to increase connectivity.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, a computerized imager is programmed with software that allows properly formatted image frames (objects) to be sent to one or more remotely located devices selected from a list of activated devices. The operator interface has two or more Print/Store buttons which are configured to respective remote devices. An image frame is selected for transfer to a particular remote device by successive operation of a Freeze button and the Print/Store button configured to that remote device. In response to operation of the chosen Print/Store button, the frozen image frame is retrieved from cine memory and stored in an image file on the imager hard disk. This procedure can be repeated to print and/or store multiple image frames for each patient.

In accordance with the preferred embodiment of the invention, for each job selected for transfer to a remote device, an element is added to a linked list which forms a virtual queue (hereinafter "Active Queue"), each element incorporating a respective pointer (i.e., the file name) identifying each stored image to be included in that particular job. Each element identifies the image frames included in the job, the destination remote device, and additional pertinent information. The Active Queue is maintained on the hard disk. In the event of a loss of power to the imager, the information stored on the hard disk will not be lost. Retention of the Active Queue (and other linked lists described hereinafter) on the hard disk enables recall, when power is restored, of the DICOM status in effect at the time of the power loss.

The imager is programmed to attempt to transfer the queued jobs in the order in which their respective elements are listed in the Active Queue. If the attempted data transfer is unsuccessful for any reason, the element for that failed job is removed from the Active Queue and added to a second linked list which constitutes a virtual holding queue (hereinafter "Holding Queue") for failed jobs. If the attempted data transfer is successful, then the successfully transferred images are automatically deleted from the hard disk. In addition, the element for this successful job is removed from the Active Queue.

In accordance with another preferred embodiment, a third linked list of elements (hereinafter "Partial Print Queue") is constructed for images making up a multi-image film session. For example, if images are to be transferred to a printer which is configured to print film sessions comprising N images, then the imager will normally not send each film session until all N images have been acquired. The file name for each of the N images is added to the Image File Name field of the element representing the particular job (i.e., film session) to which the images belong, each file name being added as that image is accumulated. When the N-th image of a film session is accumulated, the element for that film session will be deleted from the Partial Print Queue and added to the Active Queue.

The preferred embodiment of the invention further comprises software for displaying, for each destination remote device, a status menu having respective fields for indicating the number of jobs in the Active Queue and in the Holding Queue, and a field for indicating the number of images frames of a multi-image film session in the Partial Print Queue, which are directed to that particular remote device. It should be understood that status menu incorporates fields which are virtual representations of the respective queues stored in memory. However, the respective queues stored in memory list elements which point to stored images or sets (film sessions) of images destined to be sent to all activated remote devices. In contrast, the status menu has first and second fields which respectively indicate the number of jobs (single image frames or multi-image film sessions) listed in the Active and Holding Queues for each remote device individually, a third field is provided on the status menu for each printer configured to print multi-image film sessions for displaying the number of accumulated images in a film session.

In accordance with the preferred embodiment, the Active Queue field on the status menu is incremented by one (not by the number of images comprising the film session) for each multi-image film session element transferred from the Partial Print Queue to the Active Queue. If the attempt to transfer a job to a remote device fails, then the Holding Queue field on the status menu will be incremented by one and the Active Queue field on the status menu will be decremented by one.

The preferred embodiment further comprises software which allows the imager operator to redirect jobs held in any queue to any activated remote device. In particular, the operator can select the Holding Queue field of a primary remote device, select the name of a secondary remote device, and then click on a virtual representation of a Send key on the status menu. As a result of these operations, the elements listed in the Holding Queue for the primary remote device will be deleted from the Holding Queue and new elements will be added to (or an existing element revised in) the Active Queue for the secondary device. The imager will attempt to transfer any redirected job to the secondary remote device in the normal course of performing jobs.

The invention disclosed herein relates generally to imaging systems which acquire images that need to be sent to remotely located devices via a network. Although the disclosed preferred embodiment is an ultrasound imaging system, the invention has application in other types of imaging systems. Furthermore, although the preferred embodiment of the invention communicates with remote devices using the DICOM standard, the invention has application with any digital image communications standard or protocol.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a conventional ultrasound imaging system of the type which can be programmed to have DICOM capability.

FIG. 2 is a block diagram showing a typical DICOM network.

FIG. 3 is a block diagram generally depicting the hardware and software of an ultrasound imaging system in accordance with the preferred embodiment.

FIG. 4 is a schematic reproducing a "Device Configuration" menu which can be called up on the display monitor during configuration of the imaging system in accordance with the preferred embodiment.

FIG. 5 is a schematic reproducing a "DICOM Status" menu which can be called up on the display monitor to check the status of images in the imager which are waiting to be sent on the DICOM network in accordance with the preferred embodiment.

FIG. 6 is a schematic reproducing a "Device Control" menu which can be used to configure the Print/Store buttons on the operator interface in accordance with the preferred embodiment.

FIG. 7 is a schematic depicting a double-linked list stored in dynamically allocated memory space and serving as a job queue in accordance with the preferred embodiment.

FIG. 8 is a schematic reproducing a "Device Activation" menu which can be used to activate selected configured remote devices in accordance with the preferred embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a conventional computerized ultrasound imaging system which can be programmed to communicate with remote devices over a network in conformance with the DICOM standard. The type of imaging system depicted in FIG. 1 creates two-dimensional B-mode images of tissue in which the brightness of a pixel is based on the intensity of the echo return. The basic signal processing chain is as follows.

An ultrasound transducer array 2 is activated to by a transmitter in a beamformer 4 to transmit an acoustic burst which is focused at a point along a scan line. The return RF signals are detected by the transducer elements and then dynamically focused to form a receive beam by a receiver in the beamformer 4. The receive beamformer output data (I/Q or RF) for each scan line is passed through a B-mode processing chain 6, which preferably includes demodulation, filtering, envelope detection, logarithmic compression and edge enhancement.

Depending on the scan geometry, up to a few hundred receive vectors may be used to form a single acoustic image frame. To smooth the temporal transition from one acoustic frame to the next, some acoustic frame averaging 8 may be performed before scan conversion. In general, the log-compressed display data is converted by the scan converter 10 into X-Y format for video display. On some systems, frame averaging may be performed on the X-Y data (indicated by dashed block 12) rather than the acoustic frames before scan conversion, and sometimes duplicate video frames may be inserted between acoustic frames in order to achieve a given video display frame rate. The scan-converted frames are passed to a video processor 14, which maps the video data using a gray-scale mapping. The gray-scaled image frames are then sent to a video monitor 18 for display.

System control is centered in a host computer 20, which accepts operator inputs through an operator interface 22 and in turn controls the various subsystems. (In FIG. 1, only the image data transfer paths are depicted.) The operator interface comprises a keyboard, a trackball, a multiplicity of pushbuttons, and other input devices such as sliding and rotary knobs.

During imaging, a long sequence of the most recent images are stored and continuously updated automatically in a cine memory 16. Some systems are designed to save the R-θ acoustic images (this data path is indicated by the dashed line in FIG. 1), while other systems store the X-Y video images. The image loop stored in cine memory 16 can be reviewed via trackball control, and a section of the image loop can be selected for hard disk storage.

For an ultrasound imaging system which has been configured with a free-hand three-dimensional imaging capability, the selected image sequence stored in cine memory 16 is transferred to the host computer 20 for three-dimensional reconstruction. The result is written back into another portion of the cine memory, from where it is sent to the display system 18 via video processor 14.

FIG. 2 generally depicts a simplified DICOM network having an ultrasound scanner 24, a worklist broker (e.g., an RIS) 25, N storage devices 26, and M printing devices 28, all connected to a LAN 30. It will be readily appreciated that this diagram represents a simplified example of a DICOM network and that an actual DICOM network in the real world will have many more devices connected to the LAN, including modalities other than ultrasound imaging systems. The present invention is incorporated in an ultrasound imager (scanner) having the built-in capability to communicate with any one or more of the devices 25, 26 and 28 in conformance with the DICOM requirements.

A portion of such an ultrasound imager is generally depicted in FIG. 3. At the outset it should be appreciated that all of the blocks depicted in FIG. 3, with the exceptions of the cine memory 16, the display monitor 18 and the operator interface 22, are preferably incorporated in the host computer (depicted in FIG. 1 as block 20). It should be further appreciated that blocks 32, 34, and 37-42 in FIG. 3 are preferably implemented as software.

In the system depicted in FIG. 3, commands inputted via the operator interface 22 are detected and processed by a control platform 32. In return, the control platform will provide signals to the operator interface which activate various visual indicators on the operator interface to indicate the status of various functions. In response to manipulation of the appropriate key or appropriate set of keys by the operator, the DICOM presets manager 39 will display a "Device Configuration" menu (shown in FIG. 4) on the display monitor 18. The operator then enters configuration data for the first destination remote device (e.g., "Printer A" in FIG. 4) via the operator interface. Depending on whether the device being configured is a printer or storage device, the Device Type field 67 on the Device Configuration menu will be filled in with either a "Printer" or a "Storage" entry. If the device being configured is a printer which prints multi-image film sessions, then the Format field 65 in the "Printer Setup" section on the Device Configuration menu will be filled in with numbers indicating the printing format of the multi-image printer (e.g., "3×5" in the case of Printer A). For single-image printers, the entry in Format field 65 will be "1×1". A separate page of the "Device Configuration" menu will be "filled in" for each remote device which the operator wishes to configure.

The imager shown in FIG. 3 is designed to communicate with a configured remote device only if that device has been "activated". Activation causes the DICOM presets manager 39 to configure one of a multiplicity of DICOM tasks 40 in accordance with configuration data entered into the system for the associated remote device. That particular DICOM task will thereafter remain configured for that type of remote device until reconfigured for a different device. Other DICOM tasks are configured for other remote devices.

One way of activating a remote device is to click on the Activate field 66 on the Device Configuration menu to toggle the "Activate" state on. A second click on field 66 will toggle the "Activate" state off, and so forth. Alternatively, the operator can call up the Device Activation menu shown in FIG. 8, which is sent to the display monitor by the DICOM presets manager 39. The Device Activation menu comprises a list of the names of all configured remote devices, whether activated or not. A respective Activation field 100 is associated with each named device. Each Activation field 100 is a virtual representation of an Activation toggle switch. In other words, the imager is programmed with software which allows the user to activate and de-activate each configured device by simply clicking on its associated Activation field. A Yes or No is displayed in the Activation field to provide a visual indication of whether the remote device is activated.

Each activated remote device will be listed on the DICOM status menu (shown in FIG. 5) and on the Device Control menu (shown in FIG. 6). These menus are respectively sent to the display monitor by the DICOM queue manager 38 and the device control mapping manager 37. The following description assumes that the remote devices named Printer A, Printer B and Storage A have been configured and activated, while the remote devices named Printer X, Printer Y and Storage B have been configured and not activated (see FIG. 8).

Referring again to FIG. 3, the preferred embodiment is equipped with a plurality of Print/Store buttons on the operator interface 22. Each Print/Store button can be configured by the device control mapping manager 37 to initiate image transfer to more than one remote device, e.g., when a particular Print/Store button is pressed, the computer will send the corresponding acquired image to all activated remote devices configured for that button. The device control mapping manager is programmed to retrieve a Device Control menu, which is a virtual representation of the various configurations for the Print/Store buttons, from the hard disk 36 and send it to the display monitor 18. An exemplary Device Control menu for an imager having the functional equivalent of four Print/Store buttons, P1, P2, SP1 and SP2, is shown in FIG. 6. The P1 and P2 control states are respectively activated by pressing buttons P1 and P2 on the operator interface; the SP1 and SP2 control states are respectively activated by pressing buttons P1 and P2 while the Shift key is also depressed. Each of these four control states in turn can be configured so that the data of the acquired image is expressed as either color intensity values or gray-scale intensity values; so that the acquired image will be stored on the hard disk or the MOD; so that the acquired image will be transferred to one or more activated remote devices (e.g., Printers A and B and Storage A denoted in FIG. 6); or any combination of these options. For example, the imager represented in FIG. 6 is configured as follows: a color image will be transferred to Printer A and Storage A subsequent to depression of button P1; a gray-scale image will be transferred to Printer A and Storage A subsequent to depression of button P2 and the Shift key; a gray-scale image will be stored on the hard disk subsequent to depression of button P2; and a gray-scale image will be transferred to Printer B subsequent to depression of button P1 and the Shift key. Each Print/Store button configuration can be set via the operator interface. Any one of the device control fields 78 can be set by highlighting that field using the trackball and then pressing the Set key. The particular configuration of each Print/Store button is indicated by a symbol displayed in each set device control field. For each remote device ("DICOM Device" on the Device Control menu) configured to a particular Print/Store button, pressing that button after freezing an image will cause the associated DICOM task to retrieve an image file having a copy of that image from the hard disk and convert that image file to a DICOM object compatible with the associated remote device.

In accordance with the preferred embodiment, the device control mapping manager constructs a mapping of DICOM tasks (configured for respective remote devices) to Print/Store buttons. In other words, when the operator interacts with the Device Control menu (shown in FIG. 6) to configure a Print/Store button to a particular remote device, the device control mapping manager then identifies the DICOM task corresponding to that remote device and includes it in the device control mapping. The device control mapping manager 37 provides the device control mapping to the archive manager 34. When the archive manager later receives a posting from the control platform 32 that a particular Print/Store button has been pressed, the archive manager 34 will then refer to the device control mapping and determine the DICOM tasks associated with that button from the mapping. The archive manager 34 then advises the DICOM queue manager 38 which DICOM tasks 40 need to construct objects incorporating the selected image frame. The DICOM queue manager 38 then copies that image file once for each task and, if the remote devices are storage devices or single-image printers, adds a job element to the Active Queue of each task. For multi-image printers, the DICOM queue manager 38 need only add another image file name to the Image File Name field of an existing job element in the queue.

Although FIG. 3 depicts only one DICOM task, in accordance with the preferred embodiment, the imager is programmed with multiple DICOM tasks. In the preferred embodiment, one DICOM task is dedicated to worklist management and ten DICOM tasks can be configured to convert image files into either DICOM print objects or DICOM storage objects. It should be appreciated, however, that the present invention is not restricted to having ten DICOM tasks for printing and storage. In response to pressing of a Print/Store button which is configured for multiple remote devices, a corresponding multiplicity of DICOM tasks will be started substantially simultaneously. These concurrently running tasks are performed using conventional multi-tasking principles.

In accordance with the preferred embodiment, the host computer of the imager is programmed to store in memory the configuration data input via the Device Configuration menu shown in FIG. 4. For each configured remote device which is activated, a respective DICOM task is configured by the DICOM presets manager 39 in accordance with the stored configuration data. In other words, each DICOM task is partly defined by the inputs to the corresponding page of the Device Configuration menu. In particular, each DICOM task is programmed to convert an image file into a print object for printers, if "Printer" was entered in the Device Type field 67 (see FIG. 4) on the Device Configuration menu, and into a storage object for storage devices, if "Storage" was entered in the Device Type field. In the case where more than one remote device is designated to receive the same image, the associated DICOM tasks will convert respective copies of that image into respective DICOM objects acceptable to the respective remote devices.

At the beginning of every exam the system user (sonographer or sonologist) pushes a "New Patient" button, causing a menu to appear on the screen of the display monitor. The user then enters information about the patient (e.g., name, patient identifier, accession number, birthdate, etc.). When data entry is completed, the user exits the menu. At this time, a DICOM Study Instance UID is created. This Study Instance UID forms the base of the SOP Instance UID which tells the receiving DICOM device (SCP) that the image received belongs to a particular patient. Every image taken by the user, after exiting the "New Patient" menu, will have the same UID.

The examination may then begin. The user will scan the patient as needed. The user, at any time, can freeze the image and take a snapshot of that image to send to a remote device. If the receiving device is a printer, the Instance UID is not of any concern. Printers may be configured to put more than one image on a piece of film (e.g., 3×5=15 images). If this were the case, the user would normally take all 15 images before sending the completed film session to the printer.

If the receiving device is a storage device, then the SOP Instance UID will direct the image to that patient's folder of images. Storage devices receive images one at a time. The typical method of image transfer to a storage device is as follows: the DICOM task opens an association (connection) with the receiving storage device; transfer negotiations occur; the image is transferred; and the association is closed. Alternatively, the imager can be configured to open the association once and keep it open throughout the entire exam. In the latter case, the association is opened upon the sending of the first image and is closed by pressing an "End Exam" key.

The image transfer procedure used in the preferred embodiment will be described in more detail with reference to FIG. 3. In response to a request from the operator to archive a frozen image, the control platform 32 sends an "Image Store" instruction to the archive manager 34. In response to the "Image Store" instruction, the archive manager retrieves the frozen image from cine memory 16 and stores it either on the hard disk 36 or on the MOD 46, depending on the system operator's selection.

In addition, the system operator may request that the frozen image be sent to an activated remote device for printing or storage by pressing the appropriate Print/Store button. In response to a request from the operator to transfer a frozen image to a remote device, the control platform 32 sends an "Image Send" instruction to the archive manager 34. The archive manager 34 retrieves the frozen image from the cine memory 16 and stores it in a file on the hard disk 36. The file includes the image pixel data as well as certain attribute data, such as patient name, patient ID, gray-scale or color image, number of rows and columns of pixels, etc. Then the archive manager 34 notifies the DICOM queue manager 38 of the image to be transferred and the destination remote device that image (and subsequent images of the same job) will go to. Next the queue manager 38 copies the image to another location on the hard disk and gives that copied image a new file name. If the pressed Print/Store button is configured for multiple remote devices, then the queue manager 38 will store multiple copies of the frozen image in multiple files, i.e., a separate copy of the frozen image for each remote device designated as a destination for that image.

In accordance with the DICOM standard, each DICOM task is designed to convert an image file, comprising image frame data and attribute data, into a DICOM-formatted object, also comprising image frame and attribute data. That DICOM object must conform not only to the DICOM standards, but also to the attribute requirements of the remote device destined to receive that DICOM object.

In accordance with the preferred embodiment of the present invention, each DICOM task 40 has a respective Attribute Control File associated therewith. The respective Attribute Control File in turn contains a mapping of all attributes which need to be included in the DICOM objects destined for a respective remote device. Initially, when the imaging system leaves the factory, the imaging system is provided with identical Attribute Control Files. If the number of DICOM tasks is N, then (N+1) identical Attribute Control Files are stored on the hard disk 36. The first N Attribute Control Files are programmable; the (N+1)-th Attribute Control File is read only and serves as the default Attribute Control File. In the event that communication with a particular remote device is not possible due to incompatibility between the unmodified imaging system Attribute Control File and that remote device's attribute requirements, a service engineer can reprogram the particular Attribute Control File to conform to those requirements. The default Attribute Control File is used as the standard for a service engineer to copy if any of the programmable Attribute Control Files need to be reset to factory default.

Each activated configured remote device has its own Attribute Control File. This file, in ASCII format, is a mapping of which attributes should be associated with every image sent to the remote device associated with that Attribute Control File. Each DICOM task will convert each image file into a DICOM object having the acquired image data from the image file as well as the attribute data dictated by the Attribute Control File associated with that DICOM task. The data for a particular attribute may be taken from either the image file or from the Attribute Control File during construction of the DICOM object by the DICOM task.

In accordance with a further feature of the preferred embodiment, the host computer is programmed with an Attribute Control Engine 41 which controls the inclusion of particular attributes and attribute values in the DICOM objects constructed by each DICOM task 40. When the system is powered up, the Attribute Control Engine 41 reads the N Attribute Control Files associated with the N DICOM print/storage tasks are read from the hard disk 36 and written into system memory. These Attribute Control Files are kept in system memory for the duration of the power cycle.

Each Attribute Control File comprises many lines for setting up the DICOM attributes. One line is needed to set up one DICOM attribute. The format of each line is as follows:

    [Module Name] [Tag Number] [Sequence Number] [Format String]

The module name specifies the DICOM module which the attribute on that line belongs to. The module name is a defined term. The tag number specifies a particular attribute included in that module. Some DICOM attributes have the sequence of the subset of some DICOM attributes. The sequence number specifies the sequence which the attribute belongs to. The format string specifies how the data of value of the attribute should be created.

Each DICOM task 40 must receive instructions from the Attribute Control Engine 41 concerning which attributes and attribute values should be included in the DICOM object being constructed by that DICOM task.

First, the DICOM task 40 asks the Attribute Control Engine 41 whether a particular attribute should be included in the DICOM object. The Attribute Control Engine 41 refers to the associated Attribute Control File to determine whether the attribute should be included. If the attribute should not be included, the Attribute Control Engine 41 advises the DICOM task accordingly. The DICOM task 40 then proceeds to the next attribute. If the attribute should be included in the DICOM object under construction, the Attribute Control Engine 41 so advises the DICOM task 40. The DICOM task then asks the Attribute Control Engine 41 whether the value of that attribute should be obtained from the image file which is being converted or whether the attribute value should be obtained from the associated Attribute Control File. Again the Attribute Control Engine 41 refers to that associated Attribute Control File. If the attribute value should be taken from the image file, the Attribute Control Engine so advises the DICOM task. Alternatively, if the attribute value should be taken from the associated Attribute Control File, the Attribute Control Engine 41 retrieves that attribute value and sends it to the DICOM task 40.

The foregoing procedure is repeated for each attribute associated with the particular function, i.e., construction of a print object or storage object, being performed by the particular DICOM task. In other words, if the DICOM task is performing the storage function, then the DICOM task will query the Attribute Control Engine with regard to only those attributes which are relevant to the storage function. Likewise for the print function. In response to each query from the DICOM task 40 regarding a particular attribute, the Attribute Control Engine 41 will read only that line in the associated Attribute Control File corresponding to that attribute.

Referring still to FIG. 3, each DICOM task 40 sends its DICOM object in proper format to the corresponding destination remote device via the network manager 42 and the port 44. The DICOM tasks run concurrently and independently of each other in accordance with conventional multi-tasking principles.

Jobs which are waiting to be converted into DICOM objects by a DICOM task are queued in a so-called Active Queue. The queue is managed by a DICOM queue manager 38. For each job the queue manager 38 adds a separate entry in the Active Queue. In particular, each entry comprises an element having multiple fields. One of those fields lists the image file names for the images in the particular job. Each image file name serves as a pointer for retrieval from memory of the named image. Another field in the element identifies the remote device (by identifying the Task ID of the DICOM task associated with that remote device) which that stored image is destined to be sent to.

The Active Queue, Partial Print Queue and Holding Queue are preferably double-linked lists of the type depicted in FIG. 7. List 80 comprises a plurality of linked elements (e.g., elements 0 through 3) which are stored in dynamically allocated memory space on the hard disk. The term "dynamically allocated", as used herein, means that the amount of memory space allocated to store a particular list is a function of the size of the list. In other words, as more elements, corresponding to additional tasks, are added to (removed from) the list, the amount of memory space allocated to store the list is correspondingly increased (decreased). Each element comprises a data structure 82 containing patient information (for use outside of the DICOM task); a data structure 84 containing information as to the job type (print or storage); a data structure 86 containing the task ID (which is equivalent to an ID for the destination remote device, since each task corresponds to a respective destination remote device); a data structure 88 for the value representing a successful transfer to the destination remote device; a pointer 90 to the image file or files to be transferred by the identified task; a pointer 92 to the next element in the list; and a pointer 94 to the previous element in the list. The front and end of the list 80 are indicated by blocks 96 and 98 respectively.

If the remote device is a storage device or a printer which prints single images, an entry is added to the Active Queue for each image (job) selected for transfer to a remote device. If the remote device is a printer which prints multi-image film sessions, an entry is added to a Partial Print Queue for each job.

The Partial Print Queue is also preferably a linked list of elements. Copies of the Active Queue and Partial Print Queue (as well as the Holding Queue referred to later) are stored on the hard disk 36. Entries can be added at any place on the linked list. Alternatively, an element can be amended by changing the entry in a particular field. For example, a job can be redirected to a secondary remote device by changing the entry in the Task ID field. The Next or Previous pointer of any element adjacent to an added or deleted element must be changed to take account of new adjacent elements.

The Partial Print Queue is constructed of elements identifying respective multi-image film sessions. The Job Type field 84 in each element indicates whether the Image File Name field 90 contains the names of multiple images associated with a particular printing job. For example, if images are to be transferred to a printer which is configured to print film sessions comprising N images, then the imager will normally not send each film session until all N images have been acquired. The Partial Print Queue will include an element for each job. Image file names will be added to the Image File Name field 90 as the first through (N-1)-th images are accumulated. When the N-th image has been accumulated and its name has been added to the Image File Name field, the entire element will be deleted from the Partial Print Queue and added to the Active Queue.

Referring again to FIG. 3, the first job in the Active Queue is sent by the queue manager 38 to the DICOM task 40 identified by the Task ID and corresponding to the destination remote device for that first job. As previously disclosed, a separate DICOM task is configured for each remote device having a page filled out on the Device Configuration menu. When the DICOM task 40 receives a job from the Active Queue, it will read the Image File Name field (i.e., the pointer), which will contain the file name of the image to be formatted and transferred to the destination remote device. The DICOM task 40 then retrieves the image from the named file on the hard disk and reformats it into the appropriate DICOM object in accordance with the instructions from the Attribute Control Engine 41. In addition to the pixel data for the image being transferred, the DICOM object constructed by the DICOM task will include attribute data in DICOM format. If the remote device is a storage device, the DICOM task will also attach a UID to the image.

Next the DICOM task 40 will open a connection (association) to the destination remote device and negotiate a syntax. In particular, the DICOM task 40 sends a request via the network manager 42 and a port 44 that an association with the configured remote device be opened. If the remote device responds affirmatively and if a communications syntax is agreed upon, the association is opened. Once the association is open and assuming that a channel on the network is available (i.e., the network is not busy), the image is sent from the imager onto the network, again via network manager 42 and port 44. If the destination remote device sends back a message that the image transfer was successful, then the DICOM task 40 notifies the queue manager 38. The queue manager then removes the entry for the successfully transferred image from the Active Queue and deletes that image file from the hard disk 36. If the message from the destination remote device indicates that the image transfer was unsuccessful, then the queue manager 38 moves the entry for the unsuccessfully transferred image from the Active Queue to a Holding Queue and does not delete that image file from the hard disk 36. The Holding Queue is also a linked list of elements maintained both on the hard disk and in system memory. The same procedure applies when transferring a film session of multiple images to a remote printer, except that the element for the multi-image film session will be transferred to the Holding Queue unless all of the images making up the film session are transferred successfully.

In response to a view menu instruction inputted via the operator interface 22, the DICOM queue manager causes the display monitor 18 to display a DICOM status menu having entries for each remote device with queued jobs. Each entry on the status menu includes respective fields for indicating the number of jobs in the Active Queue, the number of jobs in the Holding Queue, and the number of image files in the Partial Print Queue which are directed to that particular remote device. An exemplary DICOM status menu, listing activated Printers A and B and activated Storage A, is shown in FIG. 5. The DICOM status menu includes an Active Queue field 68 and a Holding Queue field 72, as well as a Partial Print field 70 for each activated printer configured to print multi-image film sessions. The DICOM status menu also includes an Active Queue field 74 and a Holding Queue field 76 for each activated remote device configured to receive images singly (e.g., storage devices). The Active Queue field for each remote device indicates the number of jobs held in the Active Queue which are destined to be sent to that particular remote device, while the Holding Queue field indicates the number of failed jobs held in the Holding Queue and destined for that same remote device. A "job" may comprise a single image or multiple images. The Partial Print field, on the other hand, indicates the number of image files which have been acquired for constructing a particular film session (i.e., the number of image files named in the Image File Name field 90 in FIG. 7 of the corresponding list element) and the total number of image files constituting a full or complete film session for a particular printer. Since the storage devices handle single images, not multi-image film sessions, the DICOM status menu shows Partial Print fields only for printing devices.

In accordance with the preferred embodiment, in the event of a failed job (i.e., a failed attempt to transfer a single image to a single-image destination remote device or a single film session to a multi-image destination remote device), the corresponding element for that job is transferred from the Active Queue to the Holding Queue. At the same time the value indicated in the Active Queue field for that remote device will be decremented by one while the value indicated in the Holding Queue field for that remote device will be incremented by one. For example, FIG. 5 shows the status of Printer A after one failed job. Prior to the failure, the Active Queue field 68 contained the numeral 3 and the Holding Queue field 72 contained the numeral 0. Upon the failure of an attempt to send the first of three film sessions to Printer A, the number in field 68 was decreased from 3 to 2, while the number in field 72 was increased from 0 to 1.

The preferred embodiment further comprises software which allows the imager operator to redirect jobs held in the Holding Queue to a secondary remote device. For example, the operator can click on the Holding Queue field of the primary remote device, click on the name of a secondary remote device and then click on a virtual representation 75 of a Send button on the status menu. In response to these clicks, the queue manager deletes the failed job element or elements from the Holding Queue for the primary remote device, creates one or more redirected job elements configured for the secondary remote device and adds those redirected job elements to the Active Queue for that secondary remote device. In the simplest case where the primary and secondary remote devices are the same type of device, if M failed jobs in the Holding Queue of the primary remote device are redirected to the secondary device, then the number M in the Holding Queue for the primary remote device will be changed to zero and the number in the Active Queue for the secondary remote device will be incremented by M. The M corresponding elements in the Holding Queue identifying the primary remote device are deleted and M corresponding elements identifying the secondary device are added to the Active Queue. New elements can be constructed or the old elements can be reused after rewriting of the Task ID field to reflect the new destination device.

Taking another example using the numbers shown in FIG. 5, if the failed job for Printer A were redirected to Printer B, then the element for the failed job would be removed from the Holding Queue for Printer A and moved to the Active Queue for Printer B. This can be accomplished by performing the following steps in sequence: (1) manipulating the trackball to highlight the Holding Queue field 72 for Printer A on the display screen; (2) pressing the Set key on the keyboard; (3) manipulating the trackball to highlight the device name "Printer B"; (4) pressing the Set key; (5) manipulating the trackball to highlight the virtual representation 75 of the Send button; and (6) pressing the Set key. In response to these manipulations, the value indicated in the Holding Queue field 72 for Printer A would be automatically decremented from 1 to 0, while the value indicated in the Active Queue field for Printer B would be automatically incremented from 0 to 2. This is because the 15 images of the single Printer A job exceed the 8 images of a single Printer B job. Thus, Printer B will require two jobs, one with eight images and the other with seven images, in order to receive the entire redirected job. Accordingly, two new elements identifying Printer B will need to be constructed and inserted in the Active Queue. Subsequently, the imager will attempt to transfer these new jobs to Printer B in the normal course of performing jobs held in the Active Queue.

It should be understood that the new elements added to the Active Queue for the secondary device (e.g., Printer B) point to unformatted images in image files retained on the hard disk (i.e., an image file which has not yet been formatted to be compatible with the secondary device) after the unsuccessful transfer of the formatted image file to the primary device. The proper formatting for the secondary transfer occurs only when the data transfer to the secondary device is under way. As previously described, the respective DICOM task 40 for the secondary device will format the image into the appropriate DICOM object and then send that DICOM object to the over the network.

Alternatively, the operator can instruct the imager to re-attempt to transfer jobs held in the Holding Queue to the same remote device, e.g., to Printer A. This is accomplished using the same steps set forth above, except that in step (3) the trackball is manipulated to highlight the device name "Printer A" instead of "Storage A". The imager will re-attempt to transfer the pointed-to job to Printer A in the normal course of performing jobs held in the queue.

The computer software also allows the imager operator to redirect images held in the Active Queue or in the Partial Print Queue from one activated remote device to another. For example, the two jobs in the Active Queue destined for Printer A can be redirected to Printer B, in which case four elements identifying Printer B would need to be added to the Active Queue in place of the two elements identifying Printer A as the destination. Of the four jobs identified by those elements, three would have eight images each while the fourth would have only six (i.e., [3×8]+6=2×15=30).

Although the preferred embodiment employs double-linked lists, persons skilled in the art will readily appreciate that data structures other than lists (e.g., tree structures) can be used to virtually represent a queue of images. In addition, although the preferred embodiment uses separate lists for the active queue, partial print queue and holding queue, all elements could be organized in a single list, with each element having an attribute to indicate to which of the three queues the element belongs.

While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. 

What is claimed is:
 1. A method for communicating image data from an ultrasound imaging system to a remotely located device, comprising the steps of:scanning a patient with an ultrasound probe incorporated in the ultrasound imaging system; acquiring a frame of image data derived from echo signals transduced by said ultrasound probe; selecting said acquired frame of image data to be transferred to a first remotely located device; storing said selected frame of image data in memory incorporated in the ultrasound imaging system; storing a first data structure element in said memory which identifies said selected frame of image data and said first remotely located device; associating a first attribute with said first data structure element, said first attribute indicating that an attempt to send said selected frame of image data to said first remotely located device has not yet been made; initiating an attempt to send said selected frame of image data from the ultrasound imaging system to said first remotely located device; and in response to a failed attempt to send said selected frame of image data to said first remotely located device, associating a second attribute with said first data structure element, said second attribute indicating that an attempt to send said selected frame of image data to said first remotely located device has failed.
 2. The method as recited in claim 1, wherein said step of associating a first attribute with said first data structure element comprises the steps of constructing a first data structure in said memory and adding said first data structure element to said first data structure, and said step of associating a second attribute with said first data structure element comprises the steps of constructing a second data structure in said memory, adding said first data structure element to said second data structure and removing said first data structure element from said first data structure.
 3. The method as recited in claim 2, wherein said first data structure is a list of linked data structure elements, further comprising the step of linking a second data structure element to a third data structure element after removal of said first data structure element from said data structure.
 4. The method as recited in claim 2, wherein said second data structure is a list of linked data structure elements, and said step of adding said first data structure element to said second data structure comprises the step of linking said first data structure element to a second data structure element in said second data structure.
 5. The method as recited in claim 2, further comprising the step of changing said first data structure element to identify a second remotely located device instead of said first remotely located device after said first data structure element has been added to said second data structure.
 6. The method as recited in claim 2, wherein said first data structure is a first list of linked data structure elements and said second data structure is a second list of linked data structure elements, further comprising the step of dynamically allocating memory space for said first and second lists.
 7. A method for communicating image data from an ultrasound imaging system to a remotely located device, comprising the steps of:scanning a patient with an ultrasound probe incorporated in the ultrasound imaging system; acquiring frames of image data derived from echo signals transduced by said ultrasound probe; selecting a multiplicity of said acquired frames of image data to be transferred to a first remotely located device configured to receive multi-image film sessions; storing said selected multiple frames of image data in memory incorporated in the ultrasound imaging system; storing a first data structure element in said memory which identifies said selected multiple frames of image data and said first remotely located device; associating a first attribute with said first data structure element, said first attribute indicating that an attempt to send said selected multiple frames of image data to said first remotely located device has not yet been made; initiating an attempt to send said selected multiple frames of image data from the ultrasound imaging system to said first remotely located device; and in response to a failed attempt to send said selected multiple frames of image data to said first remotely located device, associating a second attribute with said first data structure element, said second attribute indicating that an attempt to send said selected multiple frames of image data to said first remotely located device has failed.
 8. An ultrasound imaging system comprising:an array of transducer elements; a transmitter programmed to transmit ultrasound wave energy into a patient during multiple scans; a receiver for acquiring multiple frames of acoustic data based on ultrasound wave energy returned from the patient during said multiple scans; a processing subsystem for forming multiple frames of image data derived from said multiple frames of acoustic data; memory for storing said multiple frames of image data; an operator interface comprising manipulatable devices for inputting instructions; control means for selecting one of said frames of image data to be transferred to a first remotely located device in response to a first instruction input via said operator interface; means for storing a data structure element in said memory which identifies said selected frame of image data and said first remotely located device; means for associating a first attribute with said data structure element, said first attribute indicating that an attempt to send said selected frame of image data to said first remotely located device has not yet been made; means for attempting to send said selected frame of image data to said first remotely located device in a first format compatible with said first remotely located device; and means for associating a second attribute with said data structure element in response to a failed attempt to send said selected frame of image data to said first remotely located device, said second attribute indicating that an attempt to send said selected frame of image data to said first remotely located device has failed.
 9. The system as recited in claim 8, wherein said means for associating a first attribute with said data structure element comprises a first data structure stored in said memory, and said means for associating a second attribute with said data structure element comprises a second data structure stored in said memory, further comprising means for adding said data structure element to said second data structure and removing said data structure element from said first data structure in response to said failed attempt.
 10. The system as recited in claim 9, further comprising means for dynamically allocating space in said memory for said first and second data structures.
 11. The system as recited in claim 9, wherein said first data structure is a first list of linked data structure elements and said second data structure is a second list of linked data structure elements.
 12. The system as recited in claim 9, wherein said control means further comprise means for changing the destination of said selected frame of image data from said first remotely located device to a second remotely located device in response to a second instruction input via said operator interface, further comprising means for changing said data structure element in said second data structure to identify said second remotely located device instead of said first remotely located device in response to said change in destination.
 13. The system as recited in claim 12, further comprising means for attempting to send said selected frame of image data to said second remotely located device in a second format compatible with said second remotely located device after said data structure element has been added to said second data structure.
 14. The system as recited in claim 8, wherein said control means further comprise means for selecting a first display mode in response to a second instruction input via said operator interface and means for selecting a second display mode in response to a third instruction input via said operator interface, further comprising:a display monitor; means for displaying said selected frame of image data on said display monitor in said first display mode; means for displaying an image transfer status menu on said display monitor in said second display mode, said image transfer status menu comprising first and second status fields associated with an identification of said first remotely located device; means for incrementing a value appearing in said first status field by unity in response to selection of said selected frame of image data for transfer to said first remotely located device; and means for decrementing said value appearing in said first status field by unity and incrementing a value appearing in said second status field by unity in response to said failed attempt.
 15. The system as recited in claim 14, wherein said control means further comprise means for changing the destination of said selected frame of image data from said first remotely located device to a second remotely located device in response to a fourth instruction input via said operator interface, and said image transfer status menu comprises a third status field associated with an identification of said second remotely located device, further comprising means for decrementing said value appearing in said second status field to zero and incrementing a value appearing in said third status field by the amount of said decrement to zero in response to said change is destination.
 16. An ultrasound imaging system comprising:an array of transducer elements; a transmitter programmed to transmit ultrasound wave energy into a patient during multiple scans; a receiver for acquiring multiple frames of acoustic data based on ultrasound wave energy returned from the patient during said multiple scans; a processing subsystem for forming multiple frames of image data derived from said multiple frames of acoustic data; memory for storing said multiple frames of image data; a display monitor; an operator interface comprising manipulatable devices for inputting instructions; control means for selecting one of said frames of image data to be transferred to a first remotely located device in response to a first instruction input via said operator interface, selecting a first display mode in response to a second instruction input via said operator interface, and selecting a second display mode in response to a third instruction input via said operator interface; means for displaying said selected frame of image data on said display monitor in said first display mode; means for displaying an image transfer status menu on said display monitor in said second display mode, said image transfer status menu comprising first and second status fields associated with an identification of said first remotely located device; means for incrementing a value appearing in said first status field by unity in response to selection of said selected frame of image data for transfer to said first remotely located device; means for attempting to send said selected frame of image data to said first remotely located device in a first format compatible with said first remotely located device; and means for decrementing said value appearing in said first status field by unity and incrementing a value appearing in said second status field by unity in response to failure of said attempt to send said selected frame of image data to said first remotely located device.
 17. The system as recited in claim 16, wherein said control means further comprise means for changing the destination of said selected frame of image data from said first remotely located device to a second remotely located device in response to a fourth instruction input via said operator interface, and said image transfer status menu comprises a third status field associated with an identification of said second remotely located device, further comprising means for decrementing said value appearing in said second status field to zero and incrementing a value appearing in said third status field by the amount of said decrement to zero in response to said change in destination.
 18. The system as recited in claim 17, further comprising means for attempting to send said selected frame of image data to said second remotely located device in a second format compatible with said second remotely located device.
 19. An image transfer system comprising:memory for storing multiple frames of image data; a display monitor; an operator interface comprising manipulatable devices for inputting instructions; control means for selecting one of said stored frames of image data to be transferred to a first remotely located device in response to a first instruction input via said operator interface, selecting a first display mode in response to a second instruction input via said operator interface, and selecting a second display mode in response to a third instruction input via said operator interface; means for displaying said selected frame of image data on said display monitor in said first display mode; means for displaying an image transfer status menu on said display monitor in said second display mode, said image transfer status menu comprising first and second status fields associated with an identification of said first remotely located device; means for incrementing a value appearing in said first status field by unity in response to selection of said selected frame of image data for transfer to said first remotely located device; means for attempting to send said selected frame of image data to said first remotely located device in a first format compatible with said first remotely located device; and means for decrementing said value appearing in said first status field by unity and incrementing a value appearing in said second status field by unity in response to failure of said attempt to send said selected frame of image data to said first remotely located device.
 20. The system as recited in claim 19, wherein said control means further comprise means for changing the destination of said selected frame of image data from said first remotely located device to a second remotely located device in response to a fourth instruction input via said operator interface, and said image transfer status menu comprises a third status field associated with an identification of said second remotely located device, further comprising means for decrementing said value appearing in said second status field to zero and incrementing a value appearing in said third status field by the amount of said decrement to zero in response to said change in destination.
 21. The system as recited in claim 20, further comprising means for attempting to send said selected frame of image data to said second remotely located device in a second format compatible with said second remotely located device.
 22. An image transfer system comprising:memory for storing multiple frames of image data; a display monitor; an operator interface comprising manipulatable devices for inputting instructions; and a computer programmed to perform the following steps: (a) selecting one of said stored frames of image data to be transferred to a first remotely located device in response to a first instruction input via said operator interface; (b) selecting a first display mode in response to a second instruction input via said operator interface; (c) selecting a second display mode in response to a third instruction input via said operator interface; (d) displaying said selected frame of image data on said display monitor in said first display mode; (e) displaying an image transfer status menu on said display monitor in said second display mode, said image transfer status menu comprising first and second status fields associated with an identification of said first remotely located device; (f) incrementing a value appearing in said first status field by unity in response to selection of said selected frame of image data for transfer to said first remotely located device; (g) attempting to send said selected frame of image data to said first remotely located device in a first format compatible with said first remotely located device; and (h) decrementing said value appearing in said first status field by unity and incrementing a value appearing in said second status field by unity in response to failure of said attempt to send said selected frame of image data to said first remotely located device.
 23. The system as recited in claim 22, wherein said computer is further programmed to perform the following steps:(i) changing the destination of said selected frame of image data from said first remotely located device to a second remotely located device in response to a fourth instruction input via said operator interface, wherein said image transfer status menu comprises a third status field associated with an identification of said second remotely located device; and (j) decrementing said value appearing in said second status field to zero and incrementing a value appearing in said third status field by the amount of said decrement to zero in response to said change in destination.
 24. The system as recited in claim 23, wherein said computer is further programmed to perform the step of attempting to send said selected frame of image data to said second remotely located device in a second format compatible with said second remotely located device.
 25. A method for communicating image data from an imaging system to a remotely located device, comprising the steps of:storing a frame of image data in memory incorporated in the imaging system; storing a first data structure element in said memory which identifies said frame of image data and said first remotely located device; associating a first attribute with said first data structure element, said first attribute indicating that an attempt to send said frame of image data to said first remotely located device has not yet been made; initiating an attempt to send said frame of image data from the imaging system to said first remotely located device; and in response to a failed attempt to send said frame of image data to said first remotely located device, associating a second attribute with said first data structure element, said second attribute indicating that an attempt to send said frame of image data to said first remotely located device has failed.
 26. The method as recited in claim 25, wherein said step of associating a first attribute with said first data structure element comprises the steps of constructing a first data structure in said memory and adding said first data structure element to said first data structure, and said step of associating a second attribute with said first data structure element comprises the steps of constructing a second data structure in said memory, adding said first data structure element to said second data structure and removing said first data structure element from said first data structure.
 27. The method as recited in claim 26, further comprising the step of changing said first data structure element to identify a second remotely located device instead of said first remotely located device after said first data structure element has been added to said second data structure.
 28. The method as recited in claim 26, wherein said first data structure is a first list of linked data structure elements and said second data structure is a second list of linked data structure elements, further comprising the step of dynamically allocating memory space for said first and second lists.
 29. An image transfer system comprising:memory for storing frames of image data; an operator interface comprising manipulatable devices for inputting instructions; and a computer programmed to perform the following steps: (a) storing a frame of image data in said memory; (b) storing a first data structure element in said memory which identifies said frame of image data and said first remotely located device; (c) associating a first attribute with said first data structure element, said first attribute indicating that an attempt to send said frame of image data to said first remotely located device has not yet been made; (d) attempting to send said selected frame of image data to said first remotely located device in a first format compatible with said first remotely located device; and (e) in response to a failed attempt to send said frame of image data to said first remotely located device, associating a second attribute with said first data structure element, said second attribute indicating that an attempt to send said frame of image data to said first remotely located device has failed.
 30. The system as recited in claim 29, wherein said step of associating a first attribute with said first data structure element comprises the steps of constructing a first data structure in said memory and adding said first data structure element to said first data structure, and said step of associating a second attribute with said first data structure element comprises the steps of constructing a second data structure in said memory, adding said first data structure element to said second data structure and removing said first data structure element from said first data structure.
 31. The system as recited in claim 30, further comprising the step of changing said first data structure element to identify a second remotely located device instead of said first remotely located device after said first data structure element has been added to said second data structure.
 32. The system as recited in claim 30, wherein said first data structure is a first list of linked data structure elements and said second data structure is a second list of linked data structure elements, and said computer is further programmed to perform the step of dynamically allocating memory space for said first and second lists.
 33. The system as recited in claim 29, wherein said computer is further programmed to perform the step of attempting to send said selected frame of image data to said second remotely located device in a second format compatible with said second remotely located device. 